Constant ratio throttle control

ABSTRACT

In a vehicle having a carburetor that includes a throttle valve, a hand lever accelerator control and an accelerator cable connected to the hand lever, apparatus for transmitting the movement of the hand lever to the carburetor throttle valve through the accelerator cable which comprises, an arm pivotally mounted to the throttle valve, means biasing said arm toward the carburetor idle position, a pulley mounted for pivotal movement and operatively connected to said arm for rotating the same, and means mounting the accelerator cable to said pulley, wherein said pulley is pivoted by manipulation of the hand lever and the pivotal movement is transmitted to the throttle valve arm.

United States Patent Anderson CONSTANT RATIO THROTTLE CONTROL [72] Inventor: George F. Anderson, York, Pa. [73] Assignee: AMF Incorporated [22] Filed: Nov. 23, 1970 [21] Appl. No.: 91,717

[52] US. Cl ..74/491, 74/489 [51] Int. Cl. ..G05g 1/00 [58] Field of Search ..74/513, 491,489, 488

[56] References Cited UNITED STATES PATENTS 2,287,704 6/1942 Oberg ..74/513 2,312,274 2/1943 Stortz ..74/513 X 2,570,429 10/1951 Cooper ..74/489 X 3,426,614 2/1969 Brilando et al. ..74/501 2,561,008 7/1951 Burrows et al ..74/488 14 Aug. 15, 1972 Primary Examiner-Milton Kaufman Assistant Examiner-Ronald C. Capossela Attorney-George W. Price and Barry H. Fishkin [57] ABSTRACT In a vehicle having a carburetor that includes a throttle valve, a hand lever accelerator control and an accelerator cable connected to the hand lever, apparatus for transmitting the movement of the hand lever to the carburetor throttle valve through the accelerator cable which comprises, an arm pivotally mounted to the throttle valve, means biasing said arm toward the carburetor idle position, a pulley mounted for pivotal movement and operatively connected to said arm for rotating the same, and means mounting the accelerator cable to said pulley, wherein said pulley is pivoted by manipulation of the hand lever and the pivotal movement is transmitted to the throttle valve arm.

3 Claims, 6 Drawing Figures PATENTEmucls I972 3,683.716.

SHEU 1 0f 4 H H H \1 m'ExToR.

GEORGE F. ANDERSON PATENTEDAUBISIBTZ 3683.716

sum 2 BF 4 FIG. 2

GEORGE F. ANDERSON Pmmimuswsmn 3.683.716

SHEET 3 UF 4 72 FIG. 4

INVENTOR GEORGE F. ANDERSON ATTORNEY PATENTEDAUB I 6 I972 3.683.716 saw u or d INVENTOR GEORGE F. ANDERSON %;iu w

' ATTORNEY CONSTANT RATIO THROTTLE CONTROL BACKGROUND This application relates to acceleration controls for vehicles and more particularly to a constant ratio acceleration control for a snowmobile.

In vehicles such as snowmobiles and the like wherein the engine is controlled by a lever attached to the handle bar of the vehicle and transmitted to the motor by a cable mounted between the lever and the carburetor throttle valve, the cable has been a chronic source of trouble and failures. This is because the attitude and position of the cable and its connection to the carburetor throttle valve have been such that a twisting load is applied thereto upon manipulation of the lever along with the longitudinal stress needed to control the engine. This twisting also leads to cable fraying and jamming, which precludes the engine from returning to idle when the accelerator lever is released. This, of course, leads to a dangerous situation wherein the vehicle does not stop as expected upon release of the hand lever.

In addition, previous acceleration control systems involved a nonJinear acceleration curve due to the geometry of the system. This is an undesirable condition because of the uncertainty in speed control that it provides.

SUMMARY It is, therefore, an object of this invention to provide an improved acceleration control for a vehicle.

It is a more specific object of this invention to provide in an acceleration control, means for maintaining the accelerator cable in an untwisted attitude.

It is a further object of this invention to provide an acceleration control having a linear acceleration and deceleration curve.

In accordance with these and other objects, apparatus according to the invention may comprise in a vehicle having a carburetor, a hand lever accelerator control and an accelerator cable connected to the hand lever, apparatus for linearly transmitting the movement of the hand lever to the carburetor throttle valve through the accelerator cable 1 comprising an arm mounted to the throttle valve, means biasing the arm toward the carburetor idle position, a pulley mounted for pivotal movement and operatively connected to said arm for rotating the same, and means mounting the accelerator cable to the pulley wherein the pulley is pivoted by manipulation of the hand lever and the pivotal movement is transmitted to the throttle valve arm.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of a snowmobile having the inventive acceleration control incorporated therein.

FIG. 2 is a plan view of a portion of a snowmobile showing the location and construction of the invention.

FIG. 3 is a side view of a carburetor showing a prior art arrangement.

FIG. 4 is a side view of a carburetor showing the acceleration control of the invention, the rod 66 which extends through swivels 67 and 69 having been broken away at its central portion.

FIG. 5 is a plan view of the carburetor shown in FIG.

FIG. 6 is a side view of a carburetor showing an alternate embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIGS. 1 and 2 of the drawings, a preferred embodiment of the invention is shown in connection with a snowmobile, but it is tobe understood that the invention could be utilized in other vehicle applications, for example, in motorcycles.

In general, a snowmobile 10 includes a frame 12, a seat 14 for the operator, and a steering handle 16 for manipulating a pair of steering skis 18 through a shaft 20 and a linkage 22. A traction belt 24 is mounted over a suspension 26 which is mounted in turn to the frame 12.

The traction belt is driven by a pair of drive sprockets 28 mounted on a shaft 30 and each engageable with a rectilinear succession of sprocket holes 32, see FIG. 2. An engine 34 having one or more carburetors 36 mounted thereto is mounted on frame 12. The engine drives the sprocket drive shaft 30 through a variable speed drive 38 and a sprocket and chain arrangement 40.

An acceleration control hand lever 42 is mounted on steering handle 16 and controls the engine speed and thus the snowmobile speed through an accelerator cable 44 connected to the engine carburetor.

In prior art systems (FIG. 3) the accelerator cable was connected at 46 directly to an arm 48 mounted on an extension of the shaft 50 of the carburetor throttle valve. Manipulation of the hand lever 42 pivoted arm 48 and the resultant rotation of shaft 50 varied engine speed. A spring 53 biased shaft 50 in a counterclockwise direction to the engine idle position and an adjustable stop 54 was provided to adjust the engine idle.

This arrangement was undesirable since it provided a non-linear control due to the movement of the connection 46 with respect to the line of the accelerator cable. This change in the position of connection 46 changes the ratio of the components of the force transmitted down the cable when the hand lever is depressed and thus changes the amplitude of the force that is applicable to rotating arm 48. This ratio change changes the amplitude of the depression of the hand lever required for an increment of throttle valve rotation and resultant engine speed.

Furthermore, with this arrangement, despite the use of a swivel connection at 46, the cable is subjected to twisting as the arm is rotated. And, this twisting is greatly amplified if the swivel jams or catches, as is likely in the conditionssurrounding normal engine use, particularly in snowmobiles.

With reference to FIGS. 2, 4, and 5, these prior art difficulties are eliminated by providing an acceleration control assembly 56 mounted between the arm 48 and the accelerator cable. The acceleration control assembly 56 includes a shaft 58 rotatably mounted between a pair of lugs 60 off the carburetor 36. A drive pulley 62 is mounted on shaft 58 and the accelerator cable is partially wrapped around the pulley and connected to a mounting 64 thereon, as shown in FIGS. 4 and 6.

The rotation of pulley 62 is transmitted to the arm 48 by a rod 66 pivotally mounted to the arm 48 at 67 by a swivel connection and pivotally mounted to a lug 68 on the shaft 58 by a swivel connection 69 such that rotation of the shaft will be transmitted to the arm 48 through the rod 66. The rigid connection between the pulley 62 and the arm 48 also transmits the counterclockwise bias provided by the spring 53 to the pulley, such that upon release of the hand lever the arm 48 and the pulley 62 will be driven back to the idle position.

It will be understood that as many lugs 68 and rods 66 can be provided as there are carburetors such that two, three or more in line carburetors can be operated in unison off a single shaft 58.

The accelerator cable 44 is mounted inside a protective plastic sleeve 70 between the hand lever and a bracket 74 adjacent the carburetor and a metal casing 72 is provided for the cable adjacent the bracket. The bracket and metal casing are positioned so that the length of the cable between the bracket and the pulley mounting 64 is held straight and in alignment with the pulley.

With this arrangement, the ratio of the components of the force transmitted down the cable will remain constant as the hand lever is depressed. Thus there will be a linear relationship between the depression of the hand lever and the movement of arm 48, resulting in a smooth and constant acceleration and deceleration. This is the result of the effective point of connection between the cable and the arm, mounting 64, remaining parallel to and in alignment with the cable as the pulley 62 rotates upon manipulation of the hand lever 42.

In another embodiment, a pulley 62 is mounted directly on the throttle valve shaft extension 50, as shown in FIG. 6. A spring 53' is mounted around the shaft extension to bias the throttle valve and pulley in a counter-clockwise direction and a stop 56 is provided to set the idle position of the carburetor. The accelerator cable is connected directly to the pulley 62' at 64 and the rotation of the cam wheel is directly transmitted to the throttle valve shaft.

Having now fully set forth both structure and operation of preferred embodiments of the concept underlying the present invention, it may be that various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will occur to those skilled in the art upon becoming familiar with said underlying concept. All such embodiments, variations, and modifications as incorporate the spirit of the invention and depend upon its underlying concept are consequently to be considered as within the scope of the claims appended herebelow, unless the claims by their language expressly state otherwise.

I claim: 1

1. In an engine having a carburetor that includes a throttle valve shaft, a hand lever accelerator control and an accelerator cable connected to the hand lever, apparatus for transmitting the movement of the hand lever to the carburetor throttle valve shaft through the accelerator cable comprising an arm mounted on said shaft, spring means biasing said arm to the carburetor idle position, a drive pulley, said cable extending from said hand lever to around said pulley and having its pulley end fixed to said pulley upon activation of said hand lever, and means providing a positive drive connection between said drive pulley and said throttle valve shaft whereby said arm is activated upon movement of said pulley by said cable.

2. In an engine as in claim 1, wherein said pulley is mounted on a second shaft separate and distinct from said throttle valve shaft, said shafts being parallel to each other, and said last mentioned positive drive connection means between said drive pulley and throttle valve shaft comprises a lug on said second shaft, and a rod extending from said lug to said arm and having a swivel connection at its opposite ends to said lug and arm.

3. In an engine as in claim 1, wherein said last mentioned means providing a positive drive connection between said drive pulley and said shaft comprises a portion of said shaft on which said drive pulley is directly mounted. 

1. In an engine having a carburetor that includes a throttle valve shaft, a hand lever accelerator control and an accelerator cable connected to the hand lever, apparatus for transmitting the movement of the hand lever to the carburetor throttle valve shaft through the accelerator cable comprising an arm mounted on said shaft, spring means biasing said arm to the carburetor idle position, a drive pulley, said cable extending from said hand lever to around said pulley and having its pulley end fixed to said pulley upon activation of said hand lever, and means providing a positive drive connection between said drive pulley and said throttle valve shaft whereby said arm is activated upon movement of said pulley by said cable.
 2. In an engine as in claim 1, wherein said pulley is mounted on a second shaft separate and distinct from said throttle valve shaft, said shafts being parallel to each other, and said last mentioned positive drive connection means between said drive pulley and throttle valve shaft comprises a lug on said second shaft, and a rod extending from said lug to said arm and having a swivel connection at its opposite ends to said lug and arm.
 3. In an engine as in claim 1, wherein said last mentioned means providing a positive drive connection between said drive pulley and said shaft comprises a portion of said shaft on which said drive pulley is directly mounted. 